This study was undertaken to evaluate glutaraldehyde preserved vascular xenografts as possible vascular substitutes in humans. Projected utilization was aimed towards replacing or bypassing arterial lumen diameters 4 mm or less and as possible arteriovenous shunts for renal dialysis. Two groups of adult dogs were acquired for short-term study. Group A received right femoral glutaraldehyde preserved interposition xenografts. In the same animal the left femoral artery was similarly replaced with an autogenous venous graft. Group B animals received femoral arteriovenous shunts constructed with glutaraldehyde preserved xenografts. All grafts remained intact for 3-8 weeks at which time they were reclaimed for histological examination. No femoral artery imposition grafts were patent, however, all contralateral venous grafts remained patent for the complete duration. All arteriovenous shunts were patent for one week after which most occluded at varying intervals.